Women truly know they have hit their 40s when they start sounding like their mum, are excited by the latest home appliances, and prefer baths to nights out.
A poll of 1,500 women aged 40 plus found 19 per cent didn’t accept they'd completed their fourth decade until they were at least two or more months into it.
With other moments of realisation including being unable to drink coffee after 4pm and having to explain just how big the Spice Girls were to those younger than them.
Going to bed before 10.30pm, realising their favourite album is 25 years old, and developing a tendency to complain about the price of things were similarly revelatory.
The research was commissioned by Vitabiotics Wellwoman Perimenopause which provides nutritional support for women before the menopause when the body begins to change.
It forms part of a campaign to raise awareness of perimenopause among women in their 40s and highlight the support available to them.
More than half (51 per cent) of those aware of perimenopause tended to think of it as something which happens to women when they get old – which 81 per cent don’t consider themselves to be.
While 12 per cent admitted they hadn’t heard of this "rarely discussed" natural stage in a woman’s life prior to taking part in the study.
Perimenopause expert Emma Bardwell, and author of The Perimenopause Solution, said: “Life is constantly teaching us new things.
"As you get older, these revelations can turn out to be real wake-up calls.
"When I entered the perimenopause at the age of 42, it was an incredibly challenging time.
"I couldn’t find the support I needed, and didn’t know where to turn.
"Women don’t always want to hear this but, if you’re in your forties, you’re likely to be perimenopausal as hormone levels are changing at that time.
"Fortunately, we now have so much more information and are better educated than ever about this time of life. And, the good news is, it’s never too early to start putting yourself - and your health - first."
Other instances where being in their 40s truly hit home, include having to look up slang used by younger people and having a predominantly 2000s and 2010s Spotify playlist.
With thinking your celeb teenage crush is now 'getting on a bit' and feeling relieved when social gatherings get cancelled similarly revelatory.
Despite these moments of realisation, 15 per cent consider their 40s to be the best years of their lives so far.
With the top three best things about this decade including caring less about what people think, appreciating the little things in life, and knowing themselves better.
It also emerged 75 per cent of those polled have taken their health more seriously than they had before since hitting 40.
And for many, perimenopause is likely to be part of their reason for prioritising this more – 50 per cent have been or going through this stage of life.
Although 80 per cent wish they had known more about it before they experienced it.
They described the experience as emotionally draining (21 per cent), physically tiring (17 per cent), and stressful (10 per cent).
Carried out through OnePoll, the research identified the one piece of advice those polled would give their younger selves, with 22 per cent revealing it would be to read more about the perimenopause.
A spokesperson for Vitabiotics Wellwoman Perimenopause, a one-a-day tablet providing 25 nutrients including vitamin B6 to help reduce tiredness and fatigue, said: “When it comes to the perimenopause, there is a clear lack of understanding, and what this means for women.
"Although some may know what the perimenopause is, this stage of life comes with plenty of myths, misconceptions, and misunderstanding.
"Advice is often lacking, and women are not sure where to turn.
"There are steps you can take for advice, with talking to a health professional a great starting point.”
TOP 40 - MOMENTS WOMEN REALISED THEY WERE IN THEIR 40s:
1. Caught yourself talking about how fast the year is going
2. Began enjoying the idea of “a quiet night in”
3. Started going to bed before 10.30
4. Realised you sound like your mum
5. I felt relieved when social events were cancelled
6. Having to look up slang used by younger family members, friends and colleagues
7. You now can’t read the ‘small print’ because it’s too small to read
8. Realised you’d rather have a nice bath than a night out
9. Realised your favourite album was 25 years old or more
10. Noticed once fashionable items of clothing had become fashionable again
11. Heard a song from your youth in a supermarket and realised it’s now considered a “classic”
12. Became more interested in healthy eating
13. Took a multivitamin as part of a new health routine
14. Realising a song you still know, all the dance moves to was released last century (e.g. Hit Me Baby One More Time, Macarena, Saturday Night)
15. Realised you couldn’t drink without getting a three-day hangover
16. Noticing you make a noise when standing up/sitting down
17. Became annoyed at forgetting reusable bags
18. You finally understood the importance of a good nap
19. Forgot your own age — more than once
20. Started using the phrase “back in my day” unironically
21. Looked forward to weekends mainly for cleaning or gardening
22. Being unable to function without your morning coffee
23. Realised you were getting irrationally excited about home appliances
24. Realised you enjoyed complaining about the price of things
25. Cared more about the weather forecast than weekend plans
26. Bought a pair of “sensible shoes” — and liked them
27. Spoke to your younger colleagues and friends about bands they knew nothing about
28. Thinking your celeb teenage crush is now “getting on a bit”
29. Started choosing seats over standing at gigs
30. Complained about modern music and how it was too loud
31. Realising people are looking to you for advice
32. Felt surprised by how young police officers’ look
33. Became irrationally worried about younger people not wearing coats in cold weather
34. Became extremely loyal to a particular brand of tea
35. Realising you had a predominantly 2000s and 2010s Spotify playlist
36. Stopped being able to drink coffee after 4pm
37. Had to explain just how big the Spice Girls were to someone younger
38. Made a conscious decision to stop dying grey hairs
39. Suddenly became more active on Facebook
40. Began treating your house plants as your children
